Skip to main content
  • Meeting abstract
  • Published:

Preload assessment in septic shock

Full text

Background

The accuracy of intra thoracic blood volume (ITBV) as a preload index, instead of central venous pressure and wedge pressure, has been demonstrated by Lichtwark-Ashoff in mechanically-ventilated patients with acute respiratory failure [1,2]. The aim of our work was: (1) to verify ITBV as a preload index in patients suffering from septic shock and (2) to relate measured data (CVP, WP, ITBV, extra vascular lung water [EVLW]), with PaO2/FiO2 ratio.

Methods

15 patients suffering from septic shock were studied. Admission criterion was septic shock refractory to standard therapy with cathecolamines. All patients were monitored with a Swan-Ganz catheter and Cold system (Pulsion, Münich) and received a bolus of methylene blue (MB) at the rate of 3 mg/Kg. Hemodynamic and oxyphoretic data were measured before MB infusion, and 20 min, 1 h and 2 h after the end of MB infusion, so that 4 sets of data for each patient were obtained to give a total of 60 data points.

Results

There is a significant correlation between ITBV and stroke volume (SV) and between ITBV and cardiac index (CI). There is also a correlation between ITBV and EVLW. No correlation was found between WP and SV and CI. Then we plotted WP vs the PaO2/FiO2 ratio and found that when the PaO2/FiO2 ratio was <200 there was no difference in EVLW between patients with WP ≤16 mmHg and patients with WP >16 mmHg. On the contrary, plotting ITBV vs PaO2/FiO2, with PaO2/FiO2 ratio>200, EVLW was very significantly higher (P<0.001) if ITBV was >1100 ml/mq, than if it was ≤1100 ml/mq.

Conclusions

In septic patients, when a respiratory failure happens, ITBV can be normal or high (>1100 ml/mq). A high ITBV is related to a high EVLW, while a high EVLW with a normal ITBV means a normal preload. In this case, it is not useful to decrease preload to increase the PaO2/FiO2 ratio. ITBV together with PaO2/FiO2 ratio is useful to optimize hemodynamic therapy during respiratory failure in septic patients and allows us to identify the patients that need diuretic therapy.

References

  1. Lichtwark-Ashoff M, et al.: . Intensive Care Med 1992, 18: 142-147. 10.1007/BF01709237

    Article  Google Scholar 

  2. Lichtwark-Ashoff M, et al.: . J Crit Care 1996, 11: 180-188. 10.1016/S0883-9441(96)90029-5

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Donati, A., Conti, G., Loggi, S. et al. Preload assessment in septic shock. Crit Care 4 (Suppl 1), P18 (2000). https://doi.org/10.1186/cc738

Download citation

  • Published:

  • DOI: https://doi.org/10.1186/cc738

Keywords